Version Bookmarks / Autosave
Autosave eliminates experimentation that can be backed out of easily. Of course you can duplicate the file before opening it and use a version file name to track, but it would be nice if this could be done within one document. If the notion strikes while working in a document, it would be nice to have a bookmark feature or the like to save the document version. Experiment from there, have the option to bookmark the experiment, go back to the first bookmark, experiment again, bookmark second experiment, compare experiments, that sort of thing.